Update dependencies for React Flight RCE advisory

Updated dependencies to fix Next.js CVE vulnerabilities.

The fix-react2shell-next tool automatically updated the following packages to their secure versions:
- next
- react-server-dom-webpack
- react-server-dom-parcel  
- react-server-dom-turbopack

All package.json files have been scanned and vulnerable versions have been patched to the correct fixed versions based on the official React advisory.

Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>

Author: vercel[bot]

package.json

@@ -32,7 +32,7 @@
     "lefthook": "^1.11.5",
     "markdown-it-mermaid": "^0.2.5",
     "mermaid": "^11.7.0",
-    "next": "^15.2.4",
+    "next": "15.2.6",
     "next-themes": "^0.4.6",
     "postcss": "^8.5.3",
     "postcss-import-url": "^7.2.0",